How to integrate QGraphicsPolygonItem with QtXML.

ShrikantAmbade

Hello Everyone,
Need help for my project. I am working on import and export of XML file. For this I am using Qt XML. My Task is to read XML file so, I am trying for XML parser which will convert it into tree structure and further this generated tree structure I have to connect with the symbols like circle, squares etc. theses symbols are already designed by using QGraphicsPolygonItem class but I am getting how can I connect generated tree structre which is repsentation of my xml with these grahical element.

Thank you so much in advance

SGaist

Hi,

Well, technically it's up to you to parse that XML and generate QGraphicsPolygonItem from the data you get. There's not much more to it unless I misunderstood your question.

ShrikantAmbade

@SGaist but how to generate QGraphicsPolygonItem?? I am am able to parse the XML file
following is the code for reading XML file just a little example this code I got and understood it. But now suppose I want to connect root element with the one of the graphical element like square. How to do that? please help with little code if you can just as example

//DOM methode of reading XML file

void ListElements(QDomElement root, QString tagname, QString attribute)
{
QDomNodeList items = root.elementsByTagName(tagname);

qDebug()<<"Total items = " << items.count();
for(int i=0; i<items.count(); i++){
    QDomNode itemnode = items.at(i);

    //convert to element
    if(itemnode.isElement())
    {
        QDomElement itemele = itemnode.toElement();
        qDebug()<<itemele.attribute(attribute);
    }
}

}

int main(int argc, char *argv[])
{
QCoreApplication a(argc, argv);

QDomDocument document;

// Load the XML file or open the XML file

QFile file("C:/Users/Shri/Desktop/QT/Myxmlexample/writexml.xml");
if(!file.open(QIODevice::ReadOnly |QIODevice::Text)){
    qDebug() << "Failed to open the file";
    return -1;
}
else{
    if(!document.setContent(&file)){
        qDebug()<<"Failed to get the content";
        return -1;
    }
    file.close();
}

//get the root elements
QDomElement root = document.firstChildElement();

//List the book element
ListElements(root,"Book","Name");

qDebug()<<"\r\n More Advance \r\n";

QDomNodeList books = root.elementsByTagName("Book");
for(int i=0; i<books.count();i++)
{
    QDomNode booknode = books.at(i);
    //convert to an element
    if(booknode.isElement())
    {
        QDomElement book = booknode.toElement();
        qDebug()<<"Chapter in " << book.attribute("Name");
        ListElements(book,"Chapter","Name");
    }
}

qDebug()<<"End Success";




return a.exec();

}

ShrikantAmbade

@SGaist This is GUI application on touch screen

SGaist

Being on a touch screen or desktop has no influence here.

In order to help get started (except taking a look at the Graphics View Framework documentation)
What do you get from your XML ? Geometries ? Coordinates ? Do you want to represent an arbitrary piece of data with some sort of picture ? e.g. a node represents a book so you want to draw a book to represent it on your scene ?

ShrikantAmbade

@SGaist Thank you so much.

For example: XML contain text data like root element and then inside that some other element and so on. When I read XML file and parse it, it store it into tree data structure with the help of DOM parser. Now after this I have root element store somewhere and also complete hierarchy is build accordingly into tree. On the other hand I have Graphical element which are just dummy symbols like circle (While I called set, this is just a name of symbol), Square (Which is represent tuples) etc. But these symbol have no identity or semantics now and Semantics is in XML which I save into Tree so I want to some how connect this two so that When I import XML file then this symbols connect with each other according to the data in XML.

I hope you understand what I want to say.. I am sorry I am bad in explaining my concept but I tried.
Many Thanks once again

SGaist

Yes I do.

For the linking part, take a look at the "Elastic Nodes" example.

As for translating your XML, you can create a subclass of QGraphicsItem which will contain the type of data it represent and draw itself accordingly.

ShrikantAmbade

@SGaist Thank you so much. Can you please give me little example any code so that I can understand it better as I am new in programming and trying to do it at my level

Many Thanks

mrjj

Hi
Maybe you can start with
http://doc.qt.io/qt-5/qtwidgets-graphicsview-diagramscene-example.html

ShrikantAmbade

@mrjj Thank you I will look into it